1. Field of the Invention
This invention relates to pumpable water-containing surfactant concentrates containing alkyl glycosides, sulfosuccinates and amphoteric surfactants, and to their use for the production of surface-active formulations.
2. Statement of Related Art
Alkyl oligoglycosides, more particularly alkyl oligoglucosides, are nonionic surfactants which are acquiring increasing significance by virtue of their excellent detergent properties and their high ecotoxicological compatibility. The production and use of these substances have been described just recently in a number of synoptic articles, of which the articles by H. Hensen in Skin Care Forum, 1, (October 1992), D. Balzer and N. Ripke in Seifen-Ole-Fette-Wachse 118, 894 (1992) and B. Brancq in Seifen-Ole-Fette-Wachse 118, 905 (1992) are cited as examples.
In some respects, however, the use of alkyl oligoglucosides is attended by problems. For example, it is not possible to produce pumpable water-containing concentrates with a solids content above 40% by weight without the sugar component undergoing partial decomposition in the course of the concentration process. The glycosides share this property with most anionic surfactants which form a viscous gel phase above an active substance content of around 35% by weight. In addition, alkyl oligoglucosides tend to crystallize during storage at low temperatures which significantly complicates their subsequent use.
Numerous surfactant mixtures containing alkyl glycosides as one component are already known from the prior art but do not solve any of the problems mentioned above.
Thus, mixtures of short-chain alkyl glycosides with sulfosuccinates for the production of hair shampoos and baby foam baths are described, for example, by G. Proserpio et al. in Rivista Italiana 56, 567 (1974). Mixtures of alkyl glycosides with sulfosuccinates for use as collectors in flotation are known from EP-A 0 219 057 (Henkel). EP-A 0 280 143 (Henkel) describes manual dishwashing detergents containing dioctyl sulfosuccinates. Mild surfactant mixtures containing sulfosuccinates, preferably monoalkyl sulfosuccinates, are claimed very broadly in EP-A 0 358 216 (Kao) and in WO 90/01441 (Henkel Corp.). The use of alkyl glycosides for regulating the viscosity of sulfosuccinate pastes is proposed in WO 91/04313 (Henkel Corp.) and in DE-A 4 007 757 (Henkel). In addition, liquid cleaning formulations which may contain alkyl glycosides and sulfosuccinates as components are known from DE-A 4 139 935 (Kao) and from EP-A 0 572 776 (Huls).
Finally, EP-A 0 453 238 (Unilever) claims mild shampoos containing anionic surfactants (for example fatty alcohol ethersulfates and sulfosuccinates), amphoteric surfactants (for example betaines) and nonionic surfactants (for example fatty alcohol polyglycol ethers and alkyl glycosides). However, the solids content of the mixtures is well below 20% by weight. In addition, combinations of alkyl glycosides, sulfosuccinates and amphoteric surfactants are not expressly mentioned.
Combinations of alkyl glycosides with amphoteric surfactants of the betaine type are described, for example, in the following documents: US 4,668,422 (Henkel Corp.), EP-A 0 250 181 (Helene Curtis), EP-A 0 341 071 (Unilever), EP-A 0 508 507 (Berol Nobel) and DE-A 4 234 487 and DE-A 4 311 114 (Henkel).
There is a need in the market for concentrated surfactant mixtures based on alkyl and/or alkenyl oligoglucosides which are flowable and pumpable, despite a solids content above 30% by weight and preferably from around 40 to 45% by weight, and show a significantly reduced tendency towards crystallization, i.e. improved stability in storage. Since surfactant compounds of the type in question are mainly used in the cosmetics field, skin-cosmetic or rather dermatological compatibility is also of paramount importance.
Surfactant concentrates are a particularly convenient commercial formulation for manufacturers and users alike because they have been minimized in regard to their water content and hence incur lower transport and storage costs. Nevertheless, it is desirable that surfactant concentrates should have a sufficiently high viscosity for use in the end products, which are of course heavily diluted and have a solids content of 20 to 30% by weight, and should be readily thickenable using known additives.
Accordingly, the complex problem addressed by the present invention was to provide pumpable water-containing surfactant concentrates with high skin cosmetic compatibility based on alkyl and/or alkenyl oligoglycosides which would be distinguished by high stability in storage, would have a Brookfield viscosity of at most 10,000 mPa.s and a solids content of 30 to 50% by weight and would readily lend themselves to thickening to a viscosity of at least 2,000 mPa.s on incorporation in cosmetic formulations with a water content of at least 50% by weight.